a) Field of the Invention
This invention relates to a switching variable magnification finder for use in photographic, video, and still video cameras.
b) Description of the Prior Art
In a camera in which a photographing optical system is in general disposed independent of a finder optical system, it is required that when the focal length of the photographing optical system is changed, the magnification of field of the finder optical system is also changed at the same time to thereby exhibit properly its photographic range. A system of switching the magnification of finder, for example, is available as follows: The finder optical system set forth in Japanese Patent Preliminary Publication No. Hei 1-255825 is designed so that an afocal auxiliary lens system is disposed removably with respect to an effective optical path of the finder optical system on the object side of an objective lens system, and inserted in or removed from the optical path in accordance with the magnification of photography, thereby switching the magnification of field.
With such a system, however, it is necessary for the optical system to secure sufficient space for the insertion or removal of the auxiliary lens system on the object side of the objective lens system fixedly disposed. Thus, the overall length of the finder optical system is greatly increased and the thickness of a camera body is difficult to be reduced, with resultant oversizing of the camera body. This offers a serious problem in view of the fact that the finder optical system of the type is often employed in small-sized cameras such as compact cameras.